Advances in the development and improvements of the luminous flux of light-emitting devices such as semiconductor, organic or polymer light-emitting diodes (LEDs) have made these devices suitable for use in general illumination applications, including architectural, entertainment, and roadway lighting, for example. As such, LEDs are becoming increasingly competitive with light sources such as incandescent, fluorescent, and high-intensity discharge lamps.
LEDs offer a number of advantages and are generally chosen for their ruggedness, long lifetime, high efficiency, low voltage requirements, and the possibility to control the colour and intensity of the emitted light independently. They provide an improvement over delicate gas discharge lamp, incandescent bulb, and fluorescent lighting systems. Solid state lighting sources have the capability to create the same lighting impressions but outweigh the drawbacks associated with the other lighting technologies.
In addition, the lighting industry has introduced ever less complicated and more standardized modular lighting components. Requirements for a vast diversity of shapes and forms of lit characters and symbols, for example, still necessitate the assembly of individually manufactured and relatively expensive letter dies in order to enable the required lighting effects. From a practical standpoint, a type of lighting technology would be desirable that allows building a solution with simpler more generic modular elements.
A number of literature references disclose light-emitting module designs for use in lighting and illumination apparatuses. For example, U.S. Pat. No. 6,837,598 describes a lighting device having a three-way conductor strip with three conductors extending in an axial direction and electrically connected at intervals to LED elements arranged in a row. Each LED element is in a plastic housing which surrounds the LED and the conductor strip, and the housing may have a lens over the LED. The housing includes two shells fixed together, and with supporting elements for an LED element, an adjacent axial conductor strip area and a heat activatable electrically conductive material. This lighting device however, does not provide a means for dissipating heat generated by the LED elements.
U.S. Pat. No. 6,660,935 describes an LED light engine which includes an electrical conductor, a flexible, electrically insulating covering surrounding the electrical conductor, and an LED. The electrical conductor includes a plurality of conductive elements. A connector is mechanically secured to the flexible insulating covering and electrically contacts the electrical conductor. The LEDs include a plurality of electrical leads, one pair of which connects the LED to a power source. Dissipation of heat generated by the LEDs is achieved using additional electrical leads. The light engine however does not provide a means for protecting the LED from the environment.
U.S. Pat. No. 6,394,626 describes an outdoor lighting display using LEDs. A flexible light track is secured at the bottom of a channel, e.g. a letter or symbol. A top corresponding to the shape of the channel covers the channel to protect the flexible light track from weather changes. The flexible light track includes a plurality of plastic modules having electrical connectors and respective tracks. LEDs are inserted in the plastic modules. Electrical wires are positioned in the tracks of the plastic modules such that the LEDs are electrically solely connected in parallel.
U.S. Patent Application Publication No. 2005/0221659 describes an LED light engine that includes a flexible electrical cable, a wire-socket assembly attached to the cable, and an LED module selectively attached to the wire-socket assembly. The wire-socket assembly includes at least two IDC terminals. The IDC terminal displaces the insulating covering of the cable and contacts one of the electrical conductors. The LED module includes an LED electrically connected to the IDC terminals when the LED module attaches to the wire-socket assembly.
U.S. Pat. No. 6,558,021 discloses LED based light-emitting modules for illuminating signs. For this configuration, however, each module requires a complicated housing that provides mechanical and electrical functionality.
The removal of heat from LEDs can lead to an increase in their longevity and brightness. A modular LED system with heat removal elements is disclosed in U.S. Pat. No. 6,712,486, for example. This patent discloses a modular LED mounting configuration including a thermally conductive body for removing heat generated by the LEDs to an adjacent heat sink. The LED module comprises a plurality of LED packages and a circuit board. The circuit board comprises electrically conductive contacts, with each contact configured to mount a lead from an LED package such that the LEDs are connected in series. A problem with this configuration is that soldering and potentially cutting of the leads are required which can be time consuming and cumbersome during installation.
U.S. Patent Application Publication No. 2003/0063463 discloses a modular LED lighting system for use in channel letter signs and lighting systems. Each module in this invention provides a thermally conductive extrusion, a printed circuit board with light-emitting devices, input and optional output wires with a combination of releasable male and female connectors. The module however, does not comprise any optical elements. In addition, a predetermined wiring length and the use of the thermally conductive extrusion to mechanically mount the module can require extra parts which can make the overall design more complicated and potentially less cost effective.
While there are many designs of light-emitting modules that facilitate heat sinking with relatively easy wiring, the prior art designs may not be simple enough to improve manufacturing, simplify assembly, and provide ease of maintenance. Therefore, there is a need for a new lighting module that provides optical, mechanical, electrical, and thermal functionality and electromechanical connectivity in a modular form.
This background information is provided to reveal information believed by the applicant to be of possible relevance to the present invention. No admission is necessarily intended, nor should be construed, that any of the preceding information constitutes prior art against the present invention.